1. Field of the Invention
The present invention pertains to bushing assemblies and, more particularly, to shoulder bushing assemblies for use in connecting joints of actuation systems, such as those found in aircraft flight control systems, which function to remove axial and radial play in the joint.
2. Discussion of the Prior Art
Bushing assemblies for use in minimizing axial and radial play in connecting joints are known in the art. In general, such bushing assemblies are utilized in mounting a shaft within a bore formed in a fixed structural member. Such bushing assemblies are located within the bore between the shaft and the fixed support member. Such known bushing assemblies are intended to be wedged between the shaft and the fixed support structure, within the bore, and tightened therein such that the wedge will function to prevent radial movement of the shaft. In addition, an axial end of the bushing engages a shoulder integrally formed with or attached to the shaft to prevent axial shifting.
In one known arrangement, the shaft comprises a bolt having a tapered section which cooperates with the wedge-shaped bushing. An example of this type of prior art arrangement is disclosed in U.S. Pat. No. 4,634,299. In this patent, a bolt or axle is radially and axially fixed within aligned bores in two spaced, fixed support members. In a first embodiment disclosed in this patent, the bolt is formed with axially spaced, oppositely tapering sections which cooperate with wedge-shaped bushing elements in order to axially and radially fix the bolt between the support members. An inner race of a bearing is supported by the bolt. In addition, the axle or bolt is formed with shoulders between its tapered sections, at least one of which engages a portion of one of the fixed support members to prevent axial shifting of the inner race.
Manufacturing bolts in accordance with the disclosure in the '299 patent is expensive due to the need for the various tapered sections and shoulder sections. The '299 patent further discusses an embodiment wherein a more readily available constant diameter bolt is utilized. In that arrangement, the bores of the fixed support members are tapered in order to cooperate with the wedge-shaped bushing members. This arrangement does not solve the problem associated with the known prior art arrangement discussed above since forming the support members with tapered bores also substantially adds to the manufacturing cost.
Therefore, there exists a need in the art for a bushing assembly for use in connecting joints which does not require either the fixed support members or the shaft to be tapered. In addition, in situations where it is desired to prevent axial shifting of a connecting joint having a bearing race, there exists a need in the art for a bushing assembly which incorporates an integral shoulder so as to minimize the number of parts.